What is Fucosidosis?

  • Canine Fucosidosis is a genetic disease which is severe, progressive and ultimately FATAL.

  • It is characterised by deteriorating signs of the nervous system that progress over a period of several months, usually from a young age. Signs include in-coordination and ataxia (loss of control of movement), change in temperament, loss of learned behaviour, loss of balance, apparent deafness, visual impairment and varying degrees of depression. The in-coordination and ataxia affects all four legs and is mostly evident when affected animals are walking on slippery surfaces or attempt more complicated movements such as turning. In addition, affected dogs lose weight and may suffer from swallowing difficulties and sometimes regurgitation of food.

  • The disease, which affects young adults, usually between 18 months and 4 years of age, is caused by the absence of an enzyme called alpha-L-fucosidase. This enzyme is one of many required to break down complex compounds into simple molecules that the body can use. When this enzyme is absent, the pathway is blocked and the more complex compounds build up in the cells of the affected animal, accumulating in the lymph nodes, liver, pancreas, kidney, lungs and bone marrow. However, it is the accumulation in the brain and peripheral nerves that is most important, since it interferes with normal function, giving rise to the clinical signs described, eventually resulting in death.

  • Canine Fucosidosis can affect all types of English Springer Spaniels, whether they are from ‘field trial', ‘working', ‘show' or ‘pet' origins.

  • All the evidence suggests that Fucosidosis is very uncommon in the UK ESS population. Nevertheless, breeders cannot afford to become complacent. This is a devastating disorder that can easily be entirely avoided.

  • The condition is inherited through a single autosomal recessive trait. In order to be clinically affected, a dog must have inherited TWO copies of the mutant Fucosidosis gene (one copy from each parent). For a further explanation of genetic inheritance, click on the icon below.

Can Fucosidosis be prevented?

A simple DNA test for Fucosidosis has been available since 1997.

A DNA test makes Fucosidosis completely preventable. The test accurately determines the genetic status of a dog as either:

  • CLEAR: The dog has two normal copies of the Fucosidosis gene. It will not have Fucosidosis, nor can it pass on a copy of the mutant gene to any offspring;

  • CARRIER: The dog has one normal copy and one mutant copy of the Fucosidosis gene. It will not clinically suffer from Fucosidosis, but it can pass on the mutant gene to its offspring;

  • AFFECTED: The dog has two mutant copies of the Fucosidosis gene. It will be clinically affected with Fucosidosis and will always pass on the mutant gene to any offspring.

Clinically affected puppies cannot be produced if at least one parent in any mating is genetically Clear.

DNA Test Procedure:

  • The Fucosidosis test uses a buccal (cheek) swab for DNA analysis, a completely non-invasive method of sample collection.

  • The sample can be collected by owners or by a qualified Vet if owners prefer the sample ID to be independently verified.

Kennel Club Recording of Fucosidosis DNA Test Results

  • An official Kennel Club Breed Scheme for Fucosidosis has been in operation since 2005, with DNA test results automatically recorded on KC registration records and published on the KC's website.

  • This enables ESS Breeders to plan their breeding programmes accordingly, making it possible to completely eradicate this fatal disease from the Breed.

  • Fucosidosis DNA testing is a requirement for the sire and dam of all ESS litters registered under the Kennel Club Assured Breeder Scheme (or they must be "hereditarily clear").

  • All ESS breeders and owners are advised to follow the Ethical Guidelines' agreed by all eight UK ESS Breed Clubs.

Useful Links

  • To find test results for individual dogs click on Health Test Results Finder.

  • To find lists of Fucosidosis tested dogs and their genetic status, click HERE. Scroll down to 'Health' and click on 'More about health', then 'Priority health schemes and tests'. **These lists do not include ‘hereditarily clear’ dogs (i.e. dogs that have themselves not been tested as they are the product of two CLEAR parents).

If any ESS owner and/or breeder needs help or further information relating to Fucosidosis, we would be happy to hear from them. We would also be extremely grateful if ESS owners would help us to monitor Fucosidosis in ESS by reporting online any confirmed diagnosis of Fucosidosis or the death of your ESS from the disease. All information provided will be treated in the strictest confidence.

For further information or advice, please contact the

ESS Breed Clubs Health Co-ordinators